Growth and phycocyanin formation of Spirulina platensis in photoheterotrophic culture

Glucose and acetate enhanced cell growth and phycocyanin production of S. platensis. The highest specific growth rate, cell concentration and phycocyanin production were respectively 0.62 d(-1), 2.66 g/l and 322 mg/l on glucose and 0.52 d(-1), 1.81 g/l and 246 mg/l on acetate. The specific growth rate of the alga on 2.5 g glucose/l was markedly increased with increasing light intensity up to 2 klux. Further increasing light intensity to 4 klux only resulted in a very slight increase in specific growth rate. At a light intensity above 4 klux, photoinhibition occurred. Light favoured phycocyanin formation. The highest phycocyanin content was obtained at a light intensity of 4 klux. When the light intensity decreased to 2 klux or less, the optimal glucose concentration for biomass production shifted from 2.5 g/l to 5.0 g/l.